Fascinating. It Does stand alone... but I would love to see the continuation. I'd love to read how Severus gets his magic back... and perhaps discover that he offers Hermione a potions apprentice to keep her near. I like how he delights in her scent left behind.

This is very good. You've got a new plot-line - something that hasn't already been done to death - and a very good grasp of your characters and their voices. You are off to a great start. I'll be following the progression of this piece.